Electrophotographic photosensitive member, process cartridge and electrophotographic apparatus

Abstract

An electrophotographic photosensitive member is provided which has a photosensitive layer formed on a support. The electrophotographic photosensitive member has a surface layer containing a silicon-containing compound or a fluorine-containing compound. The surface layer has a plurality of depressed portions which are independent from one another, on the surface. When the major axis diameter of the depressed portion is represented by Rpc and the distance between the deepest part and the opening surface of the depressed portion is represented by Rdv, Rdv is 0.1μ or more to 10.0 μm or less, and the ratio of the depth (Rdv) to the major axis diameter (Rpc), Rdv/Rpc, is more than 0.3 to 7.0 or less.

1. An electrophotographic photosensitive member comprising a support and a photosensitive layer formed on the support and containing a silicon-containing compound or a fluorine-containing compound in a surface layer in an amount of 0.6% by mass or more relative to a total solid matter of the surface layer, wherein:
 the electrophotographic photosensitive member has depressed portions which are independent from one another, in a number of from 50 or more to 70,000 or less per unit area (100 μm×100 μm), over the entire region of a surface, and, the depressed portions each have a ratio of a depth (Rdv) that shows a distance between the deepest part of each depressed portion and the opening surface thereof to a major axis diameter (Rpc) of each depressed portion, Rdv/Rpc, of from more than 0.3 to 7.0 or less, and a depth (Rdv) of from 0.1 μm or more to 10.0 μm or less; and 
 the total present ratio of a fluorine element and a silicon element relative to constitutional elements in an outermost surface of the surface layer of the electrophotographic photosensitive member obtained by x-ray photoelectron spectroscopy (ESCA) is 1.0% by mass or more; and a ratio (A/B) is larger than 0.0 and smaller than 0.5, where A (% by mass) is defined as a total content of a fluorine element and a silicon element present at a portion 0.2 μm inward from the outermost surface of the surface layer of the electrophotographic photosensitive member and B (% by mass) is defined as a total content of a fluorine element and a silicon element present in the outermost surface, with the contents of the fluorine element and silicon element obtained with x-ray photoelectron spectroscopy (ESCA). 
 
     
     
       2. The electrophotographic photosensitive member according to  claim 1 , wherein the depth (Rdv) is from 0.5 μm or more to 10.0 μm or less and the ratio of the depth (Rdv) to the major axis diameter (Rpc), Rdv/Rpc, is from more than 1.0 to 7.0 or less. 
     
     
       3. The electrophotographic photosensitive member according to  claim 1 , wherein the silicon-containing compound is a polysiloxane having at least a structural repeat unit represented by Formula (1): 
       
         
           
           
               
               
           
         
       
       in the Formula (1), R 1  and R 2  may be the same or different and represent a hydrogen atom, a halogen atom, an alkoxy group, a nitro group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group; and k represents a positive integer from 1 to 500. 
     
     
       4. The electrophotographic photosensitive member according to  claim 1 , wherein the silicon-containing compound is a polycarbonate or polyester having a structural repeat unit represented by Formula (4) below and a structural repeat unit represented by Formula (2) or (3) below: 
       
         
           
           
               
               
           
         
       
       in Formulas (2) and (3), X and Y represent a single bond, —O—, —S—, substituted or unsubstituted alkylidene group; R 3  to R 18  may be the same or different and represent a hydrogen atom, a halogen atom, an alkoxy group, a nitro group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group: 
       
         
           
           
               
               
           
         
       
       in Formula (4), R 19  and R 20  may the same or different and represent a hydrogen atom, an alkyl group or an aryl group; R 21  to R 24  may be the same or different and represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group; a represents an integer from 1 to 30; and m represents an integer from 1 to 500. 
     
     
       5. The electrophotographic photosensitive member according to  claim 4 , wherein the silicon-containing compounds comprises at least two said polycarbonates, two said polyesters, or a mixture of the polycarbonate and the polyester. 
     
     
       6. The electrophotographic photosensitive member according to  claim 4 , wherein, in the polycarbonate or polyester, a ratio of siloxane moieties relative to total structural repeat units is 10.0% by mass or more and 60.0% by mass or less. 
     
     
       7. The electrophotographic photosensitive member according to  claim 4 , wherein the silicon-containing compound is a polycarbonate or polyester having a structure represented by Formula (5) below at one of the ends or both ends: 
       
         
           
           
               
               
           
         
       
       in Formula (5), R 25  and R 26  may the same or different and represent a hydrogen atom, a halogen atom, an alkoxy group, a nitro group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group; R 27  and R 28  may be the same or different and represent a hydrogen atom, alkyl group or an aryl group; R 29  to R 33  may be the same or different and represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group; b represents an integer from 1 to 30; and n represents an integer from 1 to 500. 
     
     
       8. The electrophotographic photosensitive member according to  claim 1 , wherein the silicon-containing compound is silicone oil or modified silicone oil represented by Formula (6) below: 
       
         
           
           
               
               
           
         
       
       in Formula (6), R 34  to R 39  may be the same or different and represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group; and l represents an average value of structural repeat unit number. 
     
     
       9. The electrophotographic photosensitive member according to  claim 1 , wherein the silicon-containing compound is any one of acrylate, methacrylate and styrene, having a siloxane structure at a side chain. 
     
     
       10. The electrophotographic photosensitive member according to  claim 1 , wherein the depth (Rdv) is from more than 3.0 μm to 10.0 μm or less. 
     
     
       11. The electrophotographic photosensitive member according to  claim 1 , wherein the ratio (Rdv/Rpc), which is a ratio of the depth (Rdv) to the major axis diameter (Rpc), is from more than 1.5 to 7.0 or less. 
     
     
       12. The electrophotographic photosensitive member according to  claim 1 , wherein an average major axis diameter (Rpc-A) of the depressed portions is from 0.4 μm or more to 4.8 μm or less and an average depth (Rdv-A) of the depressed portions is from 0.8 μm or more to 8.5 μm or less. 
     
     
       13. The electrophotographic photosensitive member according to  claim 1 , wherein the surface layer contains the silicon-containing compound or the fluorine-containing compound in an amount of 0.6% by mass or more to 10.0% by mass or less relative to total solid matter of the surface layer. 
     
     
       14. The electrophotographic photosensitive member according to  claim 1 , wherein the surface layer contains a binder resin and a lubricant and the lubricant is the silicon-containing compound or the fluorine-containing compound. 
     
     
       15. A process cartridge comprising at least the electrophotographic photosensitive member according to  claim 1  and a cleaning means integrally supported, wherein the process cartridge is detachably attached to an electrophotographic apparatus main body, and the cleaning means has a cleaning blade. 
     
     
       16. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to  claim 1 , a charging means, an exposure means, a developing means, a transfer means and a cleaning means, wherein the cleaning means has a cleaning blade. 
     
     
       17. An electrophotographic photosensitive member comprising a support and a photosensitive layer formed on the support and containing a silicon-containing compound or a fluorine-containing compound in a surface layer in an amount of 0.6% by mass or more relative to a total solid matter of the surface layer, the electrophotographic photosensitive member being used in contact with a cleaning blade on the surface thereof, wherein:
 the electrophotographic photosensitive member has depressed portions which are independent from one another, in a number of from 50 or more to 70,000 or less per unit area (100 μm×100 μm), at least over the entire region of a surface portion of the electrophotographic photosensitive member which is in contact with the cleaning blade, and, the depressed portions each have a ratio of a depth (Rdv) that shows a distance between the deepest part of each depressed portion and the opening surface thereof to a major axis diameter (Rpc) of each depressed portion, Rdv/Rpc, of from more than 0.3 to 7.0 or less, and a depth (Rdv) of from 0.1 μm or more to 10.0 μm or less; and 
 the total present ratio of a fluorine element and a silicon element relative to constitutional elements in an outermost surface of the surface layer of the electrophotographic photosensitive member obtained by x-ray photoelectron spectroscopy (ESCA) is 1.0% by mass or more; and a ratio (A/B) is larger than 0.0 and smaller than 0.5, where A (% by mass) is defined as a total content of a fluorine element and a silicon element present at a portion 0.2 μm inward from the outermost surface of the surface layer of the electrophotographic photosensitive member and B (% by mass) is defined as a total content of a fluorine element and a silicon element present in the outermost surface, with the contents of the fluorine element and silicon element obtained with x-ray photoelectron spectroscopy (ESCA). 
 
     
     
       18. A process cartridge comprising at least the electrophotographic photosensitive member according to  claim 17  and a cleaning means integrally supported, wherein the process cartridge is detachably attached to an electrophotographic apparatus main body, and the cleaning means has a cleaning blade. 
     
     
       19. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to  claim 17 , a charging means, an exposure means, a developing means, a transfer means and a cleaning means, wherein the cleaning means has a cleaning blade.